Rep. Mike Simpson, R-Idaho, has co-authored a letter to Secretary of Agriculture Tom Vilsack faulting USDA for disregarding a congressional directive to add fresh white potatoes to the Special Supplemental Nutrition Program for Women, Infants and Children.

The letter by Simpson and Rep. Gregory Meeks, D-N.Y., was signed by 67 members of Congress.

The letter emphasized that 2014 appropriations bill included an “unambiguous statement” that it was the expectation of Congress that USDA include potatoes and all other vegetables in WIC, according to a press release by National Potato Council. Potatoes remain the only fresh fruit or vegetable specifically excluded from WIC packages. WIC is intended to provide nutritious food for young children and pregnant or breast-feeding mothers with low incomes.

Vilsack and Health and Human Services Secretary Kathleen Sebelius have defended their decision regarding spuds in WIC based on recommendations of a 2005 Institute of Medicine report, which found the WIC target population was already consuming enough potatoes. NPC officials noted in their press release that those IOM guidelines rely on consumption data from the mid-1990s, and eating patterns have changed since then.